Ecological buildings for Freo

PETR PACAK is Hilton resident, an architect and a building physic engineer. In this week’s THINKING ALLOWED he looks at the recent proposals for the Woolstores shopping centre redevelopment and wonders whether whether our architects are taking Australia’s climate into account, or are they a bit stuck in the old ways.

A FEW months ago, I was considering the proposed redevelopment of the Coles Woolstores site in Fremantle.

Without debating the actual architecture, I felt uncomfortable about the suggested exterior and finishes to the planned building… but why?

After all, it was leaning towards the classic ‘Freo style’ of dark red brick, Corten (fashionably rusted) metal, and other dark/black surfaces. But I guess, Freo tradition is… Freo tradition, full stop.

I’ve always liked the historical Fremantle architectural style, and many other historical architectural/urban styles which define the town’s history… giving the place a feel, spirit – the ‘genius loci’ in the ideal instance.

For this reason, I support the preservation of quality urban-architectural heritage with no hesitation.

With new developments, however, there are more important attributes to our built environment and architecture than recreating history and tradition.

These are functionality, efficiency and sustainability; all of course tied together with refined architectural form and habitable urban composition.

We are now well into the 21st century and should no longer be limited by the past imported experience of cold climate architects, builders, and tradesmen.

We’re increasingly concerned with ecological impact, the quality of our buildings, and the liveable urban environment … striving for sustainability while condemning energy inefficiency and the creation of heat islands.

Yet by adhering to our cold climate ancestors’ traditions, we’re still designing buildings not coherent with our hot and sun-abundant environment.

We’re preaching the ideal while re-erecting the past, or even worse, getting swayed by impractical fashions.

Now back to the proposed Woolstores building: the dark metal shading screens would, in summer and in direct sunlight with little wind around, reach temperatures close to 100°C. They would act as a ‘thermal radiation magnifying glass’.

But under the same conditions white or lightly coloured screens would reach temperatures of around only 50°C.

This heat re-radiation from tons of steel screens attached to the building will significantly increase the summer cooling load and extend the air conditioning run time of the building by hours each night.

Heat radiation

The difference in the amount of heat re-radiation from [mass] stored thermal energy at 50°C and 100°C is enormous – twentyfold and more (Stefan-Boltzmann Law of physics).

The dark brick façade and painted surfaces will have the same thermal effect as the metal.

We are perpetually informed about the importance and advantages of generating energy through renewable sources.

Unfortunately, there is insufficient understanding and effort (based on scientific knowledge) put into reducing energy demand in newly designed buildings in the first place.

Highly efficient LED lights save only a fraction of a building’s energy demand. Typically, over 50 per cent of the energy consumed in commercial buildings is for heating and cooling.

For these reasons, sustainability must begin with eliminating the hereditary building energy wasting culture.

It’s time to accept our climate and utilise its advantages, and work within its natural parameters.

Yes, it’s a challenge, but Fremantle council – portraying itself as progressive as well as a sustainability leader – should earnestly address the issue.

It’s not enough to be trendy, sticking photovoltaic panels wherever possible, regardless of contra-productive outer effects (and wait for Mother Nature to let enough photons through clouds at the time we need electricity).

To be progressive in this area involves defining parameters for new architectural design which will measurably reduce energy consumption.

This means prescribing roof and façade radiation reflectivity, colours, finishes with low infrared radiation absorption, and surface materials with low specific heat value.

Appropriate shading for windows, venting louvres etc. And, most importantly – learning from the traditional architecture of hot countries.

Browsing pictures of residential streets in Greece or Spain, you don’t see any red bricks, rusted steel and dark facades anywhere. The predominant colours are white and sandstone beige.

Perhaps, the ratepayer-funded local council resources would be better used in our own backyard by advancing and refining our urban environment with the local initiatives, rather than use our money for supporting “save the world” global programmes.

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